1. Field of the Invention
The present disclosure generally relates to implantable drug delivery systems and methods of using thereof.
2. Description of the Related Art
Patients with chronic disease such as cancer, AIDS, diabetes or chronic pain often require a long term and/or continuous treatment with medication. For this, drug therapy or pharmacotherapy, which is the treatment of disease through the administration of drugs, is widely employed. Particularly, chronotherapy is a treatment method in which in vivo drug availability is timed to match the rhythms of disease in order to optimize therapeutic outcomes and minimize side effects. The desirable regimen for pain relief drug or macromolecular drugs, such as insulin or growth hormones is also their delivery in a timed manner. Drug delivery system which is commonly used for timed delivery includes oral delivery systems, injection systems and implantable devices and the like.
However, oral delivery systems have some drawbacks such as low bioavailability and severe side effects due to the inactivation or degradation of the drug in the gastrointestinal passage. Injection systems, which are known for its high efficiency, also have some problems associated with the increased number of injections in order to keep the concentration of a drug at a certain level, which results in the patient inconvenience and distress. The drawbacks associated with implantable devices that can be divided active and passive types, are such that the passive types, which are designed for continuous, sustained release of a drug, is generally not suitable for the patients' driven drug delivery due to the lack of external control of drug release, and the active types are usually equipped with a controller operated by a battery to address the problem associated with the passive system, which, however, causes an additional problem due to the limited lifetime of battery, thereby needing a secondary surgery for device replacement and results in a device that is not suitable for the implantation due to the increased size by the battery.
US Patent Publication No. 2009-0209945 relates to valveless impedance pump drug delivery system and discloses a system in which a drug is released by a pressure wave reflection generated inside an elastic tube by applying the tube magnetic force and thus the system requires devices to generate and to control the impudence, which leads to a complex device with increased size.
US Patent Publication No. 2009-0209945 relates to magnetically-controllable delivery system for therapeutic agents and discloses a system wherein the agent bound to magnetizable nanoparticles is controllably delivered through a magnetizable object implanted in the body through magnetic gradient generated in the system. However this has some drawbacks that it requires a drug that is associated with magnetizable nanoparticles.
As such, there exist needs for the development of implantable drug delivery system based on magnetic force, which is small sized without battery, and internal hardware to control the device yet is able to finely control the dose of drug and the time of administration.